License Keys Explained
Note: License keys can be downloaded from

aspNetPOP3 uses a simple license key mechanism. In previous versions of aspNetPOP3, we used a license file. We decided to move to a simple alpha-numeric license key mechanism, to make it easier on developers when moving their applications (1 less file to worry about). The license key looks similar to CD license keys you may have seen on other software. For example: "aaaa-2222-cccc-3333-dddd".

To use aspNetPOP3, you need to set the license key. This can be done 1 of 2 ways. Either in code, or in your .config file.

In Code
To set your license key in code, you only need to call the following line one time. Once the license key has been validated, it is stored in memory. Calling this line multiple times will only result in unnecessary CPU cycles. We suggest you call this line in your application startup. Such as the first time you load winform or in the global.asax. If you are going to be reselling your application, this is the recommended technique, as it offers slightly better protection against some one stealing your key.


using aspNetPOP3; POP3.LoadLicenseKey("aaaa-2222-cccc-3333-dddd");

Imports aspNetPOP3 POP3.LoadLicenseKey("aaaa-2222-cccc-3333-dddd")

In your .config File
You can also set the license key in the <appSettings> section of your .config file. All you have to do, is create a key named "aspNetPOP3.LicenseKey". The first time the POP3 object is used, aspNetPOP3 will find the license key. Here is an example.

<configuration> <appSettings> <add key="aspNetPOP3.LicenseKey" value="aaaa-2222-cccc-3333-dddd"></add> </appSettings> </configuration>